Manufacturing Method of Turbine Housing
In an inner pipe assembly step, sheet-metal-made inner-pipe divided bodies and a cast inner-pipe divided body are connected to assemble an inner pipe. In a center flange connecting step, the sheet-metal-made inner-pipe divided bodies are connected to a center flange. In an outer pipe connecting step, an outer pipe covering the inner pipe is connected to the center flange and an exhaust-air-inlet-side flange. In a masking step, at least one of: a connected portion between the sheet-metal-made inner-pipe divided bodies and the cast inner-pipe divided body; or an opening portion between the outer pipe and the inner pipe is sealed. In a cutting machining step, an inner wall surface of the cast inner-pipe divided body facing the turbine wheel is subjected to a cutting machining after the masking step.
This application is a national stage 371 application of PCT/JP2018/042236, filed on Nov. 15, 2018, which claims priority to and the benefit of Japanese Application Patent Serial No. 2017-249156, filed Dec. 26, 2017, the entire disclosures of which are hereby incorporated by reference.
TECHNICAL FIELDThe present invention relates to a manufacturing method of a turbine housing used for a turbocharger (turbo-supercharger) of a vehicle.
BACKGROUNDJapanese Unexamined Patent Application Publication No. 2002-349275 proposes, for example, a turbine housing fabricated by press molded parts of steel plates in order to achieve weight reduction. In this turbine housing, each of an outer housing and an inner housing, which is encapsulated by the outer housing such that a space is formed therebetween, is formed by being divided into halved members. The halved members of the inner housing thus divided are assembled in a mutually slidable manner so as to be capable of being opened/closed. In other words, the turbine housing has a double-shell structure having the space between an inner pipe that is the inner housing and an outer pipe that is the outer housing. In addition, the inner housing is formed by welding scroll portions with each other.
SUMMARYIn a turbine housing, because a high dimensional accuracy is required for portions forming a tip clearance with a turbine wheel, a cutting machining work are required. In a case in which the turbine housing having the above-described double-shell structure is manufactured, there is a risk in that foreign matters, such as chips, etc., enter the double shell formed of an inner pipe and an outer pipe. In addition, if there is a connected portion in a scroll portion, there is a risk in that the chips, etc. enter a gap formed between members and they are trapped therein.
Thus, an object of the present invention is to provide a manufacturing method of a turbine housing in which entrance of chips, etc. formed during a cutting machining work is suppressed even in a case in which a turbine housing is formed of a plurality of members.
According to the present invention, a manufacturing method of a turbine housing includes: an inner pipe assembly step of assembling an inner pipe forming a spiral-shaped exhaust gas flow path by connecting a sheet-metal-made inner-pipe divided body and a cast inner-pipe divided body; a center flange connecting step of connecting the sheet-metal-made inner-pipe divided body to a center flange, the a center flange being configured to receive a driving shaft of a turbine wheel; an outer pipe connecting step of connecting an outer pipe covering the inner pipe to an exhaust-air-inlet-side flange and the center flange, the exhaust-air-inlet-side flange forming an exhaust-air inlet to the inner pipe; a masking step of sealing at least one of: a connected portion between the sheet-metal-made inner-pipe divided body and the cast inner-pipe divided body; or an opening portion between the inner pipe and a part of the outer pipe connected to the exhaust-air-inlet-side flange; and a cutting machining step of performing, after the masking step, cutting machining of an inner wall surface of the cast inner-pipe divided body facing the turbine wheel.
According to the present invention, it is possible to provide the manufacturing method of the turbine housing in which entrance of chips, etc. formed during a cutting machining work is suppressed even in a case in which the turbine housing is formed of a plurality of members.
An embodiment of the present invention will be described below with reference to the drawings.
A turbine housing 10 of an embodiment of the present invention will be described with reference to
The turbine housing 10 shown in
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Furthermore, a recessed portion 23c having a stepped-annular shape is formed on the exhaust-air-inlet side of the cast-metal-made third inner-pipe divided body 23, and the cylinder shaped portion (barrel shaped portion) 23d is integrally formed on the exhaust-air-outlet side of the third inner-pipe divided body 23 so as to project out therefrom. A reinforcing member (not shown) having an annular ring shape for protecting the turbine wheel 14 is fitted into the recessed portion 23c having the stepped-annular shape.
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The outer pipe 40 formed of the first outer-pipe divided body 41 and the second outer-pipe divided body 42 is welded to the center flange 11 over the entire circumference thereof, welded to the exhaust-air-inlet-side flange 12 over the entire circumference thereof, and welded to the exhaust-air-outlet-side flange 13 over the entire circumference thereof. In the above, it suffices that the outer pipe 40 is welded to the respective flanges such that the inner pipe 20 is sealed, and welding points to the respective flanges may appropriately be selected from their outer circumferences or inner circumferences.
When the turbine housing 10 is assembled, the sheet-metal-made inner-pipe divided bodies (the first inner-pipe divided body 21 and the second inner-pipe divided body 22) and the cast inner-pipe divided body (the third inner-pipe divided body 23) are connected to assemble the inner pipe 20 forming the spiral-shaped exhaust gas flow path K (an inner pipe assembly step). In addition, the sheet-metal-made inner-pipe divided bodies (the first inner-pipe divided body 21 and the second inner-pipe divided body 22) are connected to the center flange 11 receiving the driving shaft 14a of the turbine wheel 14 (a center flange connecting step). In addition, in a case in which the sheet-metal-made inner-pipe divided bodies are respectively formed of the first inner-pipe divided body 21 and the second inner-pipe divided body 22, at least abutting portions extending outward from the inner pipe 20 are respectively provided on the first inner-pipe divided body 21 and the second inner-pipe divided body 22, and these abutting portions are welded together (an welding step). Furthermore, the outer pipe 40 covering the inner pipe 20 is connected to the center flange 11 (an outer pipe connecting step).
As described above, the turbine housing 10 whose assembly (the inner pipe assembly step, the center flange connecting step, the welding step, and the outer pipe connecting step) has been completed is subjected to, in a subsequent manufacturing process, cutting machining processing of respective components (cutting machining points are shown by thick lines and a reference sign F in
After the inner pipe assembly step, but before the cutting machining step performing the cutting machining processing, at least one of: the connected portion between the sheet-metal-made inner-pipe divided body (the second inner-pipe divided body 22) and the cast inner-pipe divided body (the third inner-pipe divided body 23); or the opening portion between the inner pipe 20 and a portion of the outer pipe 40 connected to the exhaust-air-inlet-side flange 12 is sealed (masking step). In addition, in the masking step, at least the inner side of the abutting portion between the first inner-pipe divided body 21 and the second inner-pipe divided body 22 is sealed. In the cutting machining step, the cutting machining is performed on at least an inner wall surface (the front surface 23a) facing the turbine wheel 14 in the cast inner-pipe divided body (the third inner-pipe divided body 23). In addition, in the cutting machining step, it preferable to perform the cutting machining on the inner wall surface (the front surface 23a) facing the turbine wheel 14 by taking an inner circumferential surface of the center flange 11 as the reference. The cutting machining step is performed subsequent to all welding steps in the manufacturing step of the turbine housing 10. The washing operation is then performed on the turbine housing 10 after the cutting machining step (a washing step).
The masking jig 51 shown in
The masking jig 52 shown in
The masking jig 53 shown in
The masking jig 54 shown in
Next, the manufacturing steps (the cutting machining work and washing) of the turbine housing 10 using the four masking jigs 51 to 54 after the completion of the assembly will be described by following a flowchart shown in
First, as shown in
Next, an attached state of the four masking jigs 51 to 54 are checked (Step S2), and if the four masking jigs 51 to 54 are not attached at appropriate positions, the attachment of the masking jigs 51 to 54 is attempted again.
Next, in a case in which the four masking jigs 51 to 54 are attached at the appropriate positions, the cutting machining processing of the inner pipe 20, etc. is performed by a machining center, a lathe, and so forth (Step S3). When burrs are formed during the cutting machining processing, the burrs are removed.
Next, washing of the interior of the turbine housing 10 is performed using a washing machine (Step S4).
Subsequent to completion of the washing of the interior of the turbine housing 10, the four masking jigs 51 to 54 are removed (Step S5). By removing the masking jigs 51 to 54, the product that meets the standard for an amount of trapped foreign matter is completed.
Next, the four masking jigs 51 to 54 used once are checked for any damage (Step S6), and in a case in which a damage has not been caused, the four masking jigs 51 to 54 are used for the cutting machining work and the washing of the following (next) turbine housing 10. The masking jigs 51 to 54 that have been damaged are discarded, and new masking jigs 51 to 54 are used for the cutting machining work and the washing of the following turbine housing 10.
As described above, by using the four masking jigs 51 to 54 that have been formed so as match the shapes of the inner pipe 20 of the turbine housing 10 and the opening portion 12a of the exhaust-air-inlet-side flange 12, the cutting machining processing, a burr removal step, and the washing are performed on the inner pipe 20, etc. after the four masking jigs 51 to 54 are attached to the inner pipe 20 and the opening portion 12a of the exhaust-air-inlet-side flange 12, and after the cutting machining work and the washing are finished, the four masking jigs 51 to 54 are removed. By doing so, when the cutting machining work is performed on the turbine housing 10 after its assembly has been finished, it is possible to prevent entry of the foreign matter such as the chips, the burrs, and so forth, which are generated during the cutting machining, into the interior of or the space formed in the double shell formed of the inner pipe 20 and the outer pipe 40 with ease and with high reliability. With such a configuration, it is possible to perform the washing in a state in which there is no entry of the foreign matter, and it is possible to produce the product that meets the strict standard for an amount of trapped foreign matter easily, reliably, and at low cost.
In addition, because the four masking jigs 51 to 54 that match the shapes of the parts to be sealed by attaching the four masking jigs 51 to 54 to the interior of the turbine housing 10 are used, it is possible to attach the four masking jigs 51 to 54 to complex regions to be sealed easily and reliably.
In addition, because the four masking jigs 51 to 54 are of non-disposal type and they can be used multiple times repeatedly, reduction in the cost can be achieved correspondingly.
Furthermore, the masking jigs 51 to 54 are not removed even during the cutting machining work, which is performed by the machining center, the lathe, and so forth, or the washing, and therefore, it is possible to attach the masking jigs 51 to 54 reliably.
The third inner-pipe divided body and the second inner-pipe divided body may integrally be connected by using a precision casting process. Also in this case, because the first inner-pipe divided body and the second inner-pipe divided body are welded, and the first inner-pipe divided body is welded to the center flange, a positional deviation may still be caused due to accumulation of dimension errors of these components or the welding. Therefore, in order to maintain the accuracy for the tip clearance with the turbine wheel, it is effective to provide the cutting machining step.
In the above, according to the above-described embodiment, although four masking jigs are used, the number of the masking jigs is not limited to four, and at least two, or four or more masking jigs may be used. Materials of these jigs are not limited to the rubber, synthetic resin, and silicone resin.
In the above, the masking jigs may be melted and ejected to the outside of the turbine housing after the cutting machining step. If the masking jigs are not reused, it is possible to easily and reliably remove the masking jigs from the interior of the turbine housing by heating and melting them.
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In summary, according to the above-described embodiment, it is possible to provide the manufacturing method of the turbine housing in which entrance of the chips, etc. is suppressed during the cutting machining work even in a case in which the turbine housing is formed of a plurality of members.
REFERENCE SIGNS LIST
- 10: turbine housing
- 11: center flange
- 12: exhaust-air-inlet-side flange
- 12a: opening portion (inlet of exhaust gas)
- 12e: stepped portion
- 13: flange on exhaust-air-outlet side
- 13a: opening portion (outlet of exhaust gas)
- 14: turbine wheel
- 20: inner pipe (scroll portion)
- 21: sheet-metal-made first inner-pipe divided body (sheet-metal-made scroll member)
- 21c: lower end portion
- 22: sheet-metal-made second inner-pipe divided body (sheet-metal-made scroll member)
- 22c: lower end portion
- 23: cast-metal-made third inner-pipe divided body (scroll member made of cast metal, which is formed by casting as a material having higher heat resistance than material made of sheet metal)
- 25: opening portion (space)
- 40: outer pipe
- 41: sheet-metal-made first outer-pipe divided body
- 41e: lower end portion
- 42: sheet-metal-made second outer-pipe divided body
- 42e: lower end portion
- 51to 54: four masking jigs
- B: exhaust gas
- K: spiral exhaust gas flow path
- G: space
- O: spiral center portion (center portion)
- E: welded portion
Claims
1. A manufacturing method of a turbine housing comprising:
- an inner pipe assembly step of assembling an inner pipe forming a spiral-shaped exhaust gas flow path by connecting a sheet-metal-made inner-pipe divided body and a cast inner-pipe divided body;
- a center flange connecting step of connecting the sheet-metal-made inner-pipe divided body to a center flange, the a center flange being configured to receive a driving shaft of a turbine wheel;
- an outer pipe connecting step of connecting an outer pipe covering the inner pipe to an exhaust-air-inlet-side flange and the center flange, the exhaust-air-inlet-side flange forming an exhaust-air inlet to the inner pipe;
- a masking step of sealing at least one of: a connected portion between the sheet-metal-made inner-pipe divided body and the cast inner-pipe divided body; or an opening portion between the inner pipe and a part of the outer pipe connected to the exhaust-air-inlet-side flange; and
- a cutting machining step of performing, after the masking step, cutting machining of an inner wall surface of the cast inner-pipe divided body facing the turbine wheel.
2. The manufacturing method of the turbine housing according to claim 1, wherein
- the sheet-metal-made inner-pipe divided body is formed of a first inner-pipe divided body and a second inner-pipe divided body,
- in the inner pipe assembly step, abutting portions extending outward from the inner pipe are respectively provided on the first inner-pipe divided body and the second inner-pipe divided body, and the abutting portions are welded, and
- an inner side of the abutting portions is sealed in the masking step.
3. The manufacturing method of the turbine housing according to claim 1, wherein the masking step is performed by using a first masking jig and a second masking jig, the first masking jig being configured to seal a connected portion between the sheet-metal-made inner-pipe divided body and the cast inner-pipe divided body, and the second masking jig being configured to seal an opening portion between the outer pipe and the inner pipe.
4. The manufacturing method of the turbine housing according to claim 3, wherein at least one of the first masking jig or the second masking jig is used multiple times.
5. The manufacturing method of the turbine housing according to claim 3, further including a step of melting and ejecting at least one of the first masking jig or the second masking jig to outside after the cutting machining step.
6. The manufacturing method of the turbine housing according to claim 1, wherein the cutting machining of the inner wall surface is performed by taking an inner circumferential surface of the center flange as a reference.
Type: Application
Filed: Nov 15, 2018
Publication Date: Dec 17, 2020
Patent Grant number: 11421556
Inventors: Masanori Aoyama (Saitama-shi, Saitama), Hiroshi Sakurai (Saitama-shi, Saitama), Suguru Shimoda (Saitama-shi, Saitama), Keiji Kanomata (Saitama-shi, Saitama), Shin Kuwahara (Saitama-shi, Saitama), Takashi Iiya (Saitama-shi, Saitama)
Application Number: 16/956,919